Chicago, Illinois -- Thursday, June 28, 2018
Passengers on the Green Line enter West Loop, a burgeoning neighborhood on the edge of downtown Chicago.
With 8 lines stopping at 145 stations, the Chicago Transit Authority's train system -- colloquially known as the "L" -- is an essential lifeline for the city. Annually, about t238,645,800 riders use the system.
CREDIT: Alyssa Schukar for U.S. News & World Report